Ink jet printing is a non-impact and non-contact printing method in which an electronic signal controls and directs droplets or a stream of ink that can be deposited on a wide variety of substrates. Ink jet printing is extremely versatile in terms of the variety of substrates that can be treated, as well as the print quality and the speed of operation that can be achieved. In addition, ink jet printing is digitally controllable. For these reasons, ink jet methodology has been widely adopted for industrial marking and labeling. In addition, ink jet methodology has also found widespread use in architectural and engineering design applications, medical imaging, office printing (of both text and graphics), geographical imaging systems (e.g., for seismic data analysis and mapping), signage, in display graphics (e.g., photographic reproduction, business and courtroom graphics, graphic arts), and the like.
Both dyes and pigments have been used as colorants for ink jet formulations. However, such materials do not always adhere well to the substrate to which the ink is applied. For example, dyes may dissolve upon contact with water. Thus, images applied employing ink jet methodology may tend to run or smear upon repeated contact, or may actually be removed from the printed surface if exposed to substantial quantities of aqueous media (e.g., if an ink jet printed article is laundered). Moreover, images applied employing ink jet methodology may also tend to fade or washout upon prolonged exposure to visible, ultraviolet and/or infrared light.
Accordingly, there is still a need in the art for ink jet formulations which have improved adhesion properties and/or colorfastness when printed on a variety of substrates.